1. Field of the Invention
This invention is related to the area of IP Mobility. The Internet Engineering Task Force (IETF) is in the process of defining a network based mobility protocol called as Proxy Mobile Internet Protocol (IP) version 6 (PMIP6) in the Netlmm working group. Certain embodiments of the present invention are applicable in the context of the PMIP6 protocol. PMIP6 is being adopted for use in Third Generation Partnership Protocol (3GPP) and 3GPP2 architectures in addition to WiMAX.
2. Description of the Related Art
When a mobile node (MN) has multiple interfaces (for example, Institute for Electrical and Electronics Engineers (IEEE) 802.11a/b/g or generally referred to as Wireless Fidelity (WiFi), Global System for Mobile Communications (GSM), Enhanced Data rates for Global Evolution (EDGE), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), IEEE 802.16e, General Packet Radio Services (GPRS), Third Generation (3G), or the like) it is possible for the MN to attach, via these interfaces, to the appropriate access networks simultaneously. Hence a 3G MN may be connected to the Universal Mobile Telecommunications System (UMTS) packet core as well as being connected to the WiFi/802.11 network at the same time. If both these access networks supported Proxy MIP6 functionality, the MN would be attached to the Mobility Access Gateways (MAG) in these networks. When an MN attaches to a MAG, the MAG sends a Proxy Binding Update (PBU) to the Local Mobility Agent/Anchor (LMA). The identifier used in the PBU can be a common identifier across the 3G and WiFi networks. An example of such an identifier is a Network Access Identifier (NAI).
If these MAGs are served by the same Local Mobility Agent (LMA), there is no conventional way for the LMA to recognize that the Proxy Binding Updates (PBUs) being received from different MAGs are for the same MN (Identified by a common NAI across the interfaces). Thus, when the LMA receives the PBU from multiple MAGs for the same MN, the LMA conventionally would only process the last received PBU, because such is the normal behavior of the LMA. The conventional LMA cannot differentiate that the PBU is from the same MN but is sent by MAGs as a result of the MN attaching to different access networks via different interfaces from a scenario in which the connection has changed attachments. Consequently, a conventional LMA would normally delete the previous MAG entry in the Binding cache and insert the address of the MAG from the PBU that it last received.